Skew arch



v 1,634,548 r Ju y 5 1927- D. B. LUTEN v SKEW ARCH 7 Filed AuE;.2l. 1925 1 N V EN TOR. paw/EL Zu 75A A TT ORNE Y.

Patented July 5, 1927.

PATENT OFFICE.

DANIEL B. LUTEN, OF INDIANAPOLIS, INDIANA.

SKEW ARCH.

Application filed August 21, 1925.

It is the object of my invention to provide better for the unbalanced thrust which exists on the piers of a skew-arch bridge.

In carrying out my invention, I offset the footings or bases of the piers of the skew arches so that the footings or bases are more nearly perpendicular to the line of the bridge than are the piers proper. In this way, I provide more adequately for the unbalanced thrust which exists on the piers.

The accompanying drawing illustrates my invention: Fig. 1 is an elevation of a skewarch bridge constructed in accordance with my invention, the lower part of the piers and the footings for the piers being shown in section substantially on the line 1-1 of Fig. 2; and Fig. 2 is a horizontal section through the piers, substantially on the line 2-2 of Fig. 1, to show the relative arrangement of piers and footings.

The bridge is formed of a plurality of skew-arches 10, supported on piers 11 and supporting a roadway 12. The piers 11 rest on footings 13.

The piers 11 are set at oblique angles with relation to the direction of the roadway, so that the arches 10 are skew-arches. As I pointed out in my Patent No. 1,004,051, granted September 26, 1911, a skew-arch of properly bonded material. exerts greater thrust upon its abutnients or piers at its obtuse angle 14: with its abutments or piers 11 than it does at its acute angle 15 therewith. In consequence, there is an unbalanced thrust on each pier at each end thereof, the excess thrust being in one direction at one end of the pier, and in the other direction at the other end of the pier. That is, there is a greater thrust toward the right on the ends 16 of the piers 11,- and a greater thrust toward the left at the ends 17 of such piers,

as viewed in Fig. 2. These unbalanced.

thrusts create a tendency to push the ends 16 of the piers toward the right, and the ends 17 of the piers toward the left. If the bridge were divided into two halves in the vertical line of the roadway, and still func- Serial No. 51,547.

tioned as though it were monolithic, then the half pier at one end would tip in one direction and the half pier at the other end would tip in the other direction.

I resist and overcome this tipping tendency of the pier-halves by offsetting the footings of the piers as illustrated. That is,- I offset the pier footings under the pier ends 16 toward the right, and offset the pier footings under the pier ends 17 toward the left. In other words, I offset the pier footings under each end of the skew pier in the direction toward which the unbalanced thrust acts; so that by such offsetting, a pier and its footing are better able to resist the unbalanced thrust, and the resultant of the thrusts on a pier comes nearer to the line of the center of the footing at each end. In consequence, the footing as a whole is more nearly perpendicular to the roadway than is the pier itself. This is done without any increase in the quantity of materials over the footing employed for a right archthat is, one having no skew.

I claim as my invention:

l. A skew bridge, comprising a plurality of skew arches, one or more piers supporting adjacent ends of adjacent arches, said piers being oblique with respect to the roadway, and footings for said piers, said footings be ing offset from the pier so that they are inore nearly perpendicular to the roadwzr than are the piers themselves.

2. A skew bridge, comprising a plurality of skew arches, one or more piers supporting adjacent. ends of adjacent arches, footings for said piers, said piers being oblique to the direction of the roadway of the bridge, and the footing at each end of a pier being offset from the line of the pier itself toward the acute-angle side of that pier-end.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 18th day of August, A. D. one thousand nine hundred and twenty five.

DANIEL B. LUTEN. 

